Calvin cycle

noun

1. botany a series of reactions, occurring during photosynthesis, in which glucose is synthesized from carbon dioxide

Calvin cycle

1. A series of chemical reactions that occurs as part of the dark reactions of photosynthesis, in which carbon is broken away from gaseous carbon dioxide and fixed as organic carbon in compounds that are ultimately used to make sugars and starch as food. The Calvin cycle starts with a five-carbon sugar molecule, to which the carbon of carbon dioxide is attached by a covalent bond. This unstable molecule breaks apart into two three-carbon molecules, which are reduced by the electron-carriers ATP and NADPH (which were created by the earlier light reactions) into three-carbon molecules that are available for the synthesis of sugar and starch. It takes three carbon dioxide molecules to produce enough carbon for the synthesis of one of these three-carbon molecules and to regenerate the five-carbon sugar so the cycle can begin again.
2. See more at photosynthesis

Word History and Origins

Origin of Calvin cycle¹

C20: named after Melvin Calvin , who elucidated it

Example Sentences

Rubisco is one of the most important enzymes in the Calvin cycle, but the CO2 fixing enzyme is prone to errors.

From Nature

This second stage, called the Calvin cycle, could also be made more efficient.

From Nature

The second is the Calvin cycle although the name is a little unfashionable nowadays.

From Scientific American

The Calvin cycle just adds on all the extra elements required.

From Scientific American

Making sugar from carbon dioxide: The Calvin Cycle The process of photosynthesis is often described as turning sunlight into sugars, and while that’s broadly true, there are two distinct biochemical reactions taking place.

From Scientific American